OzH,
When I restored my 10 cwt GS trailer the shackle bolts, bushes and U bolts were all well beyond use and I had to have new ones made using the best originals as patterns. I went to FRM Truck and Trailer Spares in Aldershot who sent my patterns away, the results were excellent albeit not cheap. 5 years ago shackle pins were £23 and bushes £13 each
Mike